Development of UHTCMCs via water based ZrB2 powder slurry infiltration and polymer infiltration and pyrolysis

Cf/ZrB2-SiC ultra-high temperature composites were manufactured via aqueous slurry impregnation coupled with polymer infiltration and pyrolysis, using a allylhydrido polycarbosilane precursor. For the first time we used ultra-high modulus pitch-based carbon fibres for the PIP process, investigating three different architectures, 0/0°, 0/90°, and 2D. Microstructure, mechanical properties and oxidation resistance in air at 1650 °C were investigated. As expected, the mechanical properties showed the tendency to decrease with increase of the preforms complexity, due to the higher amount of flaws and residual stresses. For instance, the flexural strength was approaching 500 MPa for 0/0°, 370 MPa for 0/90° and 190 MPa for 2D. The materials showed an optimal resistance to oxidation at 1650 °C thanks to formation of a viscous borosilicate glass that guaranteed a self-healing functionality

Traumatic brain injury – global collaboration for a global challenge

Even though, low- and middle-income countries (LMICs) are facing a far greater traumatic brain injury (TBI) burden compared to high-income countries (HICs), agency funding and multi-centre research efforts have had a disproportionately greater focus on HICs.1 Initiatives, such as InTBIR,2 are advancing TBI care in HICs but the participation of LMICs has been very limited. Additionally, multicentre trials in TBI, with very few exceptions, have predominantly focused on HIC populations.NIHR Global Heath Researc

Elevated temperature tensile and bending strength of ultra-high temperature ceramic matrix composites obtained by different processes

Publisher Copyright: © 2023 Elsevier LtdThis paper presents a comparison of microstructures and mechanical properties of different ZrB2-based CMCs, which were manufactured in the frame of the Horizon 2020 European C3HARME research project through different processes: slurry infiltration and sintering (SIS), polymer infiltration and pyrolysis (PIP) and radio frequency chemical vapour infiltration (RF-CVI). Tensile testing with a novel optimized shape of the specimens was performed and compared with the results of flexural tests to assess the structural properties. For the first time, tensile tests up to 1600 °C were carried out on UHTCMCs. Despite the different microstructural features, all the ZrB2-based CMCs demonstrated excellent structural properties even at elevated temperature. The characterization shows how the different amount of porosity and fibre properties, such as its stiffness, strength and elongation, affected the mechanical behaviour of the C3HARME's composites. Finally, the role of the high level of residual thermal stresses is discussed.This work has received funding from the European Union’s Horizon 2020 “Research and innovation programme” under grant agreement No 685594 (C3HARME). The authors greatly acknowledge Airbus Defence and Space GmbH for the collaboration and supplying materials. This work has received funding from the European Union's Horizon 2020 “Research and innovation programme” under grant agreement No 685594 (C3HARME). The authors greatly acknowledge Airbus Defence and Space GmbH for the collaboration and supplying materials.Peer reviewe

Predicting intracranial lesions by antiplatelet agents in subjects with mild head injury

International audienceBackground: The effect of pre-injury antiplatelet treatment in the risk of intracranial lesions in subjects after mild head injury (Glasgow Coma Scale 14-15) is uncertain. Methods: We aimed to determine the potential risk, considering its increasing use in guidelines on cardiovascular disease prevention and aging of the trauma population in Europe. Patients: We analyzed the interaction of antiplatelet therapy with the prediction variables of main decision aids in 14,288 consecutive adolescent and adult subjects with mild head injury. Measurements: Any intracranial lesion at CT scan was selected as outcome measure in a multivariable logistic regression analysis. Findings: Intracranial lesions were demonstrated in 880 cases (6.2%), with an unfavorable outcome at 6 months in 86 (0.6%). Antiplatelet drugs were recorded in 10% of the entire cohort (24.7% in the group over 65 years). They increased the risk of intracranial lesions at univaried analysis (odds ratio - OR, 2.6; 95% confidence interval - 95% CI 2.2¨C3.1), interacting with age at multivariate analysis (antiplatelet: OR, 2.7 (1.9¨C3.7); age ¡Ý 75 years, 1.4 (1.0¨C1.9)). The inclusion of these two variables to those included in previous decision aids for CT scanning (GCS, neurodeficit, post-traumatic seizures, suspected skull fracture, vomiting, loss of consciousness, coagulopathy) predicted intracranial lesions with a sensitivity of 99.7% (95% CI 98.9¨C99.8) and a specificity of 54.0% (95%CI 53.1¨C54.8), with a CT ordering-rate of 49.3% (undetermined events, 0.2:1000). Interpretation: Antiplatelet drugs need to be considered in future prediction models on mild head injury, considering their increasing use and progressive aging of the trauma populatio

Towards an Efficient Finite Element Method for the Integral Fractional Laplacian on Polygonal Domains

We explore the connection between fractional order partial differential equations in two or more spatial dimensions with boundary integral operators to develop techniques that enable one to efficiently tackle the integral fractional Laplacian. In particular, we develop techniques for the treatment of the dense stiffness matrix including the computation of the entries, the efficient assembly and storage of a sparse approximation and the efficient solution of the resulting equations. The main idea consists of generalising proven techniques for the treatment of boundary integral equations to general fractional orders. Importantly, the approximation does not make any strong assumptions on the shape of the underlying domain and does not rely on any special structure of the matrix that could be exploited by fast transforms. We demonstrate the flexibility and performance of this approach in a couple of two-dimensional numerical examples

On the Dynamics of solitons in the nonlinear Schroedinger equation

We study the behavior of the soliton solutions of the equation i((\partial{\psi})/(\partialt))=-(1/(2m)){\Delta}{\psi}+(1/2)W_{{\epsilon}}'({\psi})+V(x){\psi} where W_{{\epsilon}}' is a suitable nonlinear term which is singular for {\epsilon}=0. We use the "strong" nonlinearity to obtain results on existence, shape, stability and dynamics of the soliton. The main result of this paper (Theorem 1) shows that for {\epsilon}\to0 the orbit of our soliton approaches the orbit of a classical particle in a potential V(x).Comment: 29 page

High sensitivity C-reactive protein increases the risk of carotid plaque instability in male dyslipidemic patients

Background: The aim of this study was to evaluate how the high sensitivity C-reactive protein (hs-CRP) values influence the risk of carotid plaque instability in association with other cardiovascular risk factors. Methods: One hundred and fifty-six carotid plaques from both symptomatic and asymptomatic patients requiring surgical carotid endarterectomy were retrospectively collected. According to the modified American Heart Association, atherosclerosis plaques have been histologically distinguished into unstable and stable. The following anamnestic and hematochemical data were also considered: age, gender, hypertension, diabetes mellitus, smoking habit, therapy, low-density lipoprotein (LDL)-C, kidney failure and hs-CRP. Results: The results of our study clearly show that high levels of hs-CRP significantly increase the carotid plaque instability in dyslipidemic patients. Specifically, a 67% increase of the risk of carotid plaque instability was observed in patients with high LDL-C. Therefore, the highest risk was observed in male dyslipidemic patients 2333 (95% CI 0.73-7.48) and in aged female patients 2713 (95% CI 0.14-53.27). Discussion: These data strongly suggest a biological relationship between the hs-CRP values and the alteration of lipidic metabolism mostly in male patients affected by carotid atherosclerosis. The measurement of hs-CRP might be useful as a potential screening tool in the prevention of atheroscletotic disease

Social media for dissemination and public engagement in neurosurgery-the example of Brainbook.

BACKGROUND: Public engagement has become one of the most effective tools in gaining feedback and perspectives from members of the public, involving patients with decisions, and inspiring young people to carry the medical profession forwards. Brainbook is a multi-platform, social media-based resource that was created specifically to enhance public engagement in neurosurgery and results from one of its case discussions will be reported in this paper. METHODS: A Brainbook case was created in collaboration with the NIHR Global Health Research Group on Neurotrauma and presented over 3 days (23-25 February 2018). YouTube videos were created depicting the management of an acute subdural haematoma using patient interviews, medical illustration, consultant-led discussion and operative footage. Content was shared across all Brainbook social media platforms and analytics were gathered through social media applications. RESULTS: Over a 72-hour time period, and across multiple social media accounts, 101,418 impressions were achieved (defined as penetrance onto individual media feeds and total views of the content), with active discussion on social media. CONCLUSIONS: Neurosurgical content published across multiple social media outlets represents an encouraging and exciting potential for global engagement across multiple audiences. Social media can be an effective method of not only disseminating neurosurgical knowledge, but activating and engaging the public, allied healthcare professionals, medical students and neurosurgeons